Liquid container

ABSTRACT

It is constructed such that a closed space ( 12   b ) of an inner container ( 12 ) having a heat retaining property which constitutes a liquid container ( 1 B) is able to be closed airtightly by closing of a lid structure ( 141 ). Contact between stored liquid and the atmosphere is shut off by making the inside of the closed space be in an inert gas atmosphere. It is constructed such that the stored liquid is able to be discharged by pressure of supplied inert gas at a time of opening of a discharge valve ( 168 ) communicating with the inner container. Oxidation deterioration of liquid is effectively prevented by shut-off from the atmosphere. When the stored liquid is discharged in small portions, preventive effect is maintained by continual supply of inert gas.

TECHNICAL FIELD

The present invention relates to a liquid container for storing various liquids for beverages such as coffee and tea and liquid for other than beverage use and, more particularly to a liquid container capable of restraining quality deterioration by oxidation (oxidation deterioration) of stored liquid.

BACKGROUND ART

As a liquid container for storing liquid for beverage, there is a push-type thermos pot for domestic use (see FIG. 1 of Japanese Patent Application Laid-open No. Hei 7-163471). This type of liquid container is generally used to store hot water for brewing coffee, tea or the like, but it may be used to store coffee, tea or the like instead of hot water.

However, if coffee of approximately 90 degrees for example is stored in a conventional liquid container, color of the coffee changes or taste thereof gets worse with time. This is mainly because air (oxygen) in the liquid container reacts and deteriorates (oxidize) coffee, and has been regarded as a problem. In cases of other beverages such as tea, the same problem as in the case of coffee occurs. Further, not only in a case of storing liquid in high temperature but also in a case of storing liquid such as soft drink in low temperature, the problem of deterioration is pointed out as well.

DISCLOSURE OF THE INVENTION

An object of the present invention is to solve the above-described problem. More specifically, it is the object of the present invention to provide a liquid container capable of restraining oxidation deterioration of liquid stored in the liquid container effectively and maintaining the restraining effect when the stored liquid is discharged in small portions.

In order to achieve the above-described object, in the present invention the inside of the liquid container is constructed as a closed space shut off from the atmosphere, and additionally, it is constructed such that the atmosphere (air) in the closed space is able to be substituted with inert gas. Since contact of the atmosphere and the stored liquid can be shut off thereby, oxidation deterioration can be restrained effectively. Detailed constructions will be described in other sections. It should be noted that definitions or the like of terms for explaining any claimed invention also apply to other claimed inventions within possible ranges of their nature.

ASPECTS OF FIRST CLAIMED INVENTION

A liquid container according to a first claimed invention (hereinafter, referred to as “the liquid container of the first invention” accordingly) includes: an outer container; an inner container having a heat retaining property which is housed in the outer container; a lid structure capable of forming a closed space in the inner container by closing an upper opening of the inner container airtightly in an openable/closable manner; a gas supply means for supplying inert gas of a predetermined pressure into the closed space of the inner container; a valve structure enabling the closed space of the inner container and the outside to be communicated; a draw pipe for guiding liquid stored in the inner container to out of the outer container via the closed space; and a discharge valve provided to the draw pipe. It is characterized in that by such a constitution it is constructed such that the stored liquid is able to be discharged by pressure of supplied inert gas at a time of opening of the discharge valve. The heat retaining property of the inner container is a concept including both of a heat retaining property which the container itself has and a heat retaining property maintained by a heating device or cooling device. The “lid structure” refers to every member that is able to be constructed by a single or a plurality of member(s) and to be able to close an opening of the inner container directly or indirectly. Opening/closing of the valve structure may be automatic or manual. Additionally, the valve structure may have a function as a purge valve for letting out inside gas when pressure inside the closed space exceeds a predetermined value.

According to the liquid container of the first invention, after the lid structure is opened and liquid is supplied into the inner container, the lid structure is closed. At this time, there is formed a closed space in which the atmosphere is sealed in the inner container. When the valve structure is opened, the inside and outside of the inner container temporarily communicate with each other, and at this time inert gas is supplied into the closed space by the gas supply means. By supplying of inert gas, the atmosphere in the closed space gradually flows out to the outside through the valve structure. When the inside of the closed space becomes in an inert gas atmosphere (dilution of the atmosphere by inert gas), the valve structure is closed, so that contact of the liquid in the inner container and the atmosphere is shut off to effectively restrain deterioration of liquid over the future. On the other hand, the closed space is maintained in a predetermined pressure (pressure higher than the atmosphere) by inert gas. When the discharge valve is opened, the stored liquid having received the pressure of inert gas via a liquid surface is pushed up into the draw pipe by the pressure of inert gas. The liquid pushed up then flows through the closed space while being guided by the draw pipe, and is withdrawn (discharged) to the outside from the discharge valve. Withdrawal of liquid is terminated by closing of the discharge valve. Inert gas is continually supplied into the closed space, so that volume corresponding to withdrawn volume of liquid is replenished. Hereby, the inside of the closed space is maintained in the predetermined pressure. When the discharge valve is opened/closed again according to the above-described procedure, liquid can be withdrawn any number of times as long as the stored liquid remains. At a time of another withdrawal, inert gas of volume corresponding to withdrawn volume is supplied, so that the pressure inside the closed space is maintained constant. The atmosphere does not enter the closed space at the time of liquid withdrawal. The stored liquid is kept warm by the heat retaining property of the inside container, and deterioration is restrained by action of inert gas. The liquid container of the first invention can store liquid supplied into the inner container for a long time without changing temperature and quality at a time of supply as much as possible. Further, since long-time storage is possible and it is avoided to dispose liquid due to lowered quality, which may be required if long-time storage is impossible, it can prevent economic loss by disposal.

ASPECTS OF SECOND CLAIMED INVENTION

A liquid container according to a second claimed invention (hereinafter, referred to as “the liquid container of the second invention” accordingly) is the liquid container of the first invention, and characterized in that the lid structure includes a purge valve purging automatically when the pressure of the closed space is at a predetermined value and above.

According to the liquid container of the second invention, in addition to the operation and effect of the liquid container of the first invention, it is possible to purge gas in the closed space automatically to make the pressure back to the predetermined value and below if the pressure inside the closed space rises to the predetermined value and above for some reason. More specifically, if the pressure in the closed space rises to the predetermined value and above, inconveniences are anticipated such as, for example, at a time of liquid withdrawal the liquid to be withdrawn erupts abruptly and sprinkled, but by maintaining the pressure at the predetermined value and below, such an inconvenience can be prevented from occurring. It also contributes to enhance safety.

ASPECTS OF THIRD CLAIMED INVENTION

A liquid container according to a third claimed invention (hereinafter, referred to as “the liquid container of the third invention” accordingly) is the liquid container of the first invention or the second invention, and characterized in that the lid structure includes a pressurizing structure for pressurizing supplied inert gas. The pressurizing structure may be provided in either a case that pressure of the supplied inert gas only is sufficient for liquid withdrawal or a case that the pressure of the supplied inert gas is not sufficient for withdrawal and it is used to heighten the pressure to a sufficient level.

According to the liquid container of the third invention, in addition to the operation and effect of the liquid container of the first invention or the second invention, the pressure of the supplied inert gas can be heightened by pressurizing of the pressurizing structure. In the case that the pressure of the supplied inert gas only is sufficient for liquid withdrawal the pressurizing structure enables smoother withdrawal by heightening the pressure, while in the case that it is used to heighten the pressure to the sufficient level since the pressure of the supplied inert gas is not sufficient for withdrawal the pressurizing structure enables withdrawal by pressurizing.

ASPECTS OF FOURTH CLAIMED INVENTION

A liquid container according to a fourth claimed invention (hereinafter, referred to as “the liquid container of the fourth invention” accordingly) is the liquid container of the third invention, and characterized in that the pressurizing structure includes bellows between a top plate and a bottom plate and it is constructed such that an air pump and the closed space are able to be communicated via an opening formed in the bottom plate. The top plate and the bellows, and the bottom plate and the bellows, respectively, can be easily manufactured of synthetic resin by integral molding, for example, but they can be manufactured by other methods. Further, the top plate or the bottom plate is not necessarily a single plate, but modification is possible accordingly.

According to the liquid container of the fourth invention, in addition to the operation and effect of the liquid container of the third invention, the bellows retract to shorten a distance between the top plate and the bottom plate by the top plate being pushed down directly or indirectly. That is, volume of the inside of the air pump is reduced. By this reduction, the inert gas in the air pump is pushed to the closed space via the opening, so that inert gas pressure in the closed space is heightened by just that much. More specifically, the inert gas is pressurized and this pressure realizes smooth withdrawal of liquid. Though the structure is simple, according to the air pump, pressurizing of the inert gas can be performed effectively.

ASPECTS OF FIFTH CLAIMED INVENTION

A liquid container according to a fifth claimed invention (hereinafter, referred to as “the liquid container of the fifth invention” accordingly) is the liquid container of the third invention or the fourth invention, and characterized in that the discharge valve is constituted with a check valve opening automatically in an automatically recoverable manner by the pressurizing of the inert gas by the pressurizing structure. The pressurizing may be continual, intermittent, wave-like, and so on.

According to the liquid container of the firth invention, in addition to the operation and effect of the liquid container of the third invention or the fourth invention, when the pressurizing by the pressurizing structure is performed, in response thereto the discharge valve opens to allow withdrawal of liquid. When the pressurizing is terminated, or the pressure which has been once pressurized drops to a predetermined value and below due to liquid withdrawal, the discharge valve automatically returns to a closed state to prevent liquid withdrawal. Since the discharge valve is a check valve, it allows liquid withdrawal but prevents the atmosphere which tries to flow in a reverse direction against the withdrawal.

ASPECTS OF SIXTH CLAIMED INVENTION

A liquid container according to a sixth claimed invention (hereinafter, referred to as “the liquid container of the sixth invention” accordingly) is the liquid container of any one of the third invention to the fifth invention, and characterized in that the gas supply means includes a gas passage and a gas supply source sending inert gas to the closed space, a check valve for gas being provided in the gas passage.

According to the sixth invention, in addition to the operation and effect of the liquid container of any one of the third invention to the fifth invention, the pressure of the inert gas in the closed space is heightened by the pressurizing of the pressurizing means, and by this heightened pressure the inert gas is prevented from flowing reversely in the gas passage. Therefore, a liquid container without a pressurizing means does not necessarily include a check valve for gas since reverse flow by pressurizing does not occur. Reverse flow of inert gas may not occur for reasons such as the pressure of the inert gas supplied from the gas supply source is higher than pressure of the inert gas trying to flow reversely, but by providing the check valve for gas it is avoided to impose an extra burden on the gas supply source. Therefore, for example, it becomes possible to simplify a structure of the gas supply source or to adopt one with low supply capacity of gas.

ASPECTS OF SEVENTH CLAIMED INVENTION

A liquid container according to a seventh claimed invention (hereinafter, referred to as “the liquid container of the seventh invention” accordingly) is the liquid container of any one of the first invention to the sixth invention, and characterized in that the gas supply means is provided with a regulator for adjusting the pressure of the inert gas.

According to the liquid container of the seventh invention, in addition to the operation and effect of the liquid container of any one of the first invention to the sixth invention, by providing the regulator, pressure adjustment of the inert gas and adjustment of amount supplied along therewith can be performed accurately and smoothly. Accurate and smooth supply of the inert gas stabilizes the pressure of inert gas in the closed space. Consequently, stable storage and smooth withdrawal of the stored liquid are enhanced.

ASPECTS OF EIGHTH CLAIMED INVENTION

A liquid container according to an eighth claimed invention (hereinafter, referred to as “the liquid container of the eighth invention” accordingly) is the liquid container of the first invention or the second invention, and characterized in that the pressure of the inert gas in the closed space is set to be 0.001 to 0.1 MPa, more preferably, at 0.003 MPa and below. The pressure of the inert gas is adequate if it is higher than atmospheric pressure, and though it is not intended to limit the pressure within this range, it is preferable to set the pressure within the above-described range for smooth withdrawal of liquid.

According to the liquid container of the eighth invention, the operation and effect of the liquid container of the first invention or the second invention occur smoothly, since the pressure of the inert gas in the closed space is set to be 0.001 to 0.1 MPa. More specifically, it is because: in order to push up the stored liquid the pressure of supplied inert gas is required to be higher than atmospheric pressure, and if the pressure is below 0.001 MPa it takes too much time to withdraw liquid due to too weak pressure, which is not regarded as smooth, and if the pressure exceeds 0.1 MPa liquid may be sprinkled at a time of discharge from the discharge valve due to too high pressure, which is not regarded as smooth. It is a matter of course, however, whether withdrawal is smooth varies according to dispositions (types of ingredients, difference of viscosity) of liquid to be withdrawn, a diameter of the draw pipe, a shape of the discharge valve, and the like.

ASPECTS OF NINTH CLAMED INVENTION

A liquid container according to a ninth claimed invention (hereinafter, referred to as “the liquid container of the ninth invention” accordingly) is the liquid container of any one of the first invention to the eighth invention, and characterized in that the lid structure includes a pouring check valve for pouring liquid into the closed space.

According to the liquid container of the ninth invention, in addition to the operation and effect of the liquid container of any one of the first invention to the eighth invention, opening/closing of the lid structure is not necessarily performed, since liquid can be poured into the inner container via the pouring check valve. The opening of the lid structure is convenient for cleaning and the like of the inside of the inner container and liquid pouring is possible by opening of the lid structure, but liquid pouring via the pouring check valve may be sometimes more convenient than pouring in association with the opening of the lid structure. Further, in the case of pouring with the opening of the lid structure, since the atmosphere enters the inner container by the opening thereof, withdrawing operation of the atmosphere is required such as opening the valve structure again, but by pouring liquid via the pouring check valve so as not to allow the atmosphere to enter, liquid can be stored and discharged without withdrawing operation of the atmosphere. This is quite convenient since the effort of withdrawing the atmosphere can be saved, not only in a case of pouring liquid into an empty inner container but also in a case of replenishing liquid into an inner container in which liquid still remains. Incidentally, the pouring check valve is constructed to allow only pouring, and the inert gas in the closed space does not flows outside.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view of a liquid container according to the present embodiment;

FIG. 2 is an enlarged view of a part of the liquid container;

FIG. 3 is an enlarged view of a part of the liquid container;

FIG. 4 is a plan view of the liquid container;

FIG. 5 is a vertical cross-sectional view showing withdrawal of air of the liquid container;

FIG. 6 is an enlarged view of a part of the vertical cross-section and a bottom view of the liquid container;

FIG. 7 is a vertical cross-sectional view of a bottom member;

FIG. 8 is a vertical cross-sectional view of a liquid container according to a first modification example;

FIG. 9 is a vertical cross-sectional view of the liquid container according to the first modification example;

FIG. 10 is a front view of the liquid container;

FIG. 11 is a plan view of the liquid container;

FIG. 12 is a piping diagram showing flow of inert gas;

FIG. 13 is a vertical cross-sectional view of a liquid container according to a second modification example;

FIG. 14 is a vertical cross-sectional view of the liquid container according to the second modification example;

FIG. 15 is a table showing a list of analyzers for analyzing over-time change of stored coffee being stored liquid;

FIG. 16 is tables showing results of analysis; and

FIG. 17 is charts showing results of sensory evaluation.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention (hereinafter, referred to as “the present embodiment” accordingly) will be described with reference to the drawings.

(Schematic Construction of Liquid Container)

A schematic constitution of a liquid container will be described based on FIG. 1 and FIG. 2. A liquid container 1 is formed into approximately the same outer appearance as that of a thermos pot (vacuum pot) for domestic use or business use, and is substantially constituted with: an outer container 2 composing the outer appearance; an inner container 12 with heat retaining property which is housed in the outer container 2; a lid structure 7 capable of forming a closed space 12 b in the inner container 12 by closing an upper opening 12 a of the inner container 12 airtightly in an openable/closable manner; a shoulder member 8 disposed between an upper portion of the outer container 2 and the lid structure 7; a draw pipe (draw tube) 21 for guiding liquid stored in the inner container 12 out of the outer container 2 via the closed space 12 b; and a first valve structure (check valve for discharging liquid) 80 provided to the draw pipe 21. The outer container 2 can be manufactured by processing a steel or synthetic resin, while the inner container 12 is constituted with a vacuum double glass bottle to maintain the heat retaining property (constant temperature property). The inner container 12 can be provided with a heater (depiction omitted) and the like to retain heat.

The shoulder member 8 is made of integrally molded synthetic resin, and is formed into an approximate funnel (sprinkler) shape as a whole, and a lower portion thereof is constructed to function as a first valve structure 80 and a second valve structure 90 described later. To be more precise, the shoulder member 8 has a flat upper surface 8 a and an inner surface 8 b inclining downward toward a center, and in addition, also includes a liquid supply surface 8 c inclining steeply from the inner surface 8 b toward the upper opening 12 a of the inner container 12. Further, the shoulder member 8 includes a discharge tube cover 9 protruding forward (to the observer's left in FIG. 1) to cover a discharge tube 22 described later. On the liquid supply surface 8 c, there are formed a liquid discharge port 8 d which the draw pipe 21 is made pass through in a state of maintained airtightness, and a gas supply port 8 e for supplying inert gas (nitrogen gas). The draw pipe 21 extends downward to a vicinity of a bottom portion of the inner container 12, and the upper portion thereof is bent in a horizontal direction toward the discharge tube cover 9. A horizontal part bent from the draw pipe 21 becomes a part which passes through the liquid discharge port 8 d, maintaining airtightness. The liquid discharge port 8 d and the gas supply port 8 e are disposed in such a position at which they face each other across the upper opening 12 a of the inner container 12. On a lower portion of the liquid supply surface 8 c, there is provided a liquid supply portion 10 capable of covering an upper end portion of the inner container 12 in such a manner to sandwich it from the inside and outside of the container. Between the liquid supply portion 10 and the upper end part of the inner container 12, a sealing member 10 a is interposed to maintain airtightness between the both.

The first valve structure 80 is constructed as a check valve for discharging liquid which allows liquid to be discharged from the draw pipe 21 to the outside but does not allow the atmosphere to enter in a reverse direction. More specifically, the first valve structure 80 includes a communicating path 80 a communicating linearly from the left to right direction in FIG. 2, a valve ball moving path 80 b, a slide supporting path 80 c and a coil housing chamber 80 d, each shape of vertical cross-sections of these spaces being circular. The communicating path 80 a is a part directly communicating with an end-point of the draw pipe 21, and an inside diameter of the valve ball moving path 80 b continuing therefrom is set to be larger than an inside diameter of the communicating path 80 a. A sealing member 80 s is disposed on a step portion between the communicating path 80 a and the valve ball moving path 80 b caused by a difference of the inside diameters, and on the sealing member 80 s, a through hole (depiction omitted) through which liquid can pass is formed. On the other hand, an inside diameter of the slide supporting path 80 c is set to be smaller than the inside diameter of the valve ball moving path 80 b, and therefore a step portion also exists between these. The valve ball moving path 80 b is constructed such that a valve ball 81 is movable there in a longitudinal direction of the moving path, and an diameter of the valve ball 81 is set to be larger than both of the inside diameter of the communicating path 80 a and the inside diameter of the slide supporting path 80 c. Therefore, moving of the valve ball 81 is limited to between the sealing member 80 s existing between the communicating path 80 a and the valve ball moving path 80 b, and the slide supporting path 80 c. The valve ball 81 can be constructed of metal or is synthetic resin for example, of an approximately completely round shape. To the valve ball 81, there is fixed an end of a crossbar 82 a of an operating body 82 (described later) which is supported to be able to slide airtightly by the slide supporting path 80 c, and it is constructed such that the valve ball 81 moves by moving of the valve operating body 82. Another end of the crossbar 82 a is fixed to a coil spring 80 f in the coil housing chamber 80 d, and it is constructed such that the coil spring 80 f biases the crossbar 82 a in a closing direction (from the left to right direction in FIG. 1), to thereby press the valve ball 81 on the sealing member 80 s. By the valve ball 81 being pressed on the sealing member 80 s, the through hole (depiction omitted) of the sealing member 80 s is constantly closed. In order to open the through hole of the sealing member 80 s, it is necessary to move the vale ball 81 in an opening direction (from the right to left direction in FIG. 1) against biasing force of the coil spring 80 f, and this becomes possible at a time of liquid discharge. This point will be described later. Incidentally, the valve ball moving path 80 b communicates with the discharge tube 22 via a drop hole 80 h penetrating a bottom portion of the valve ball moving path 80 b. More specifically, by the valve ball 81 moving in the opening direction, the inside of the draw pipe 21 is communicated with the valve ball moving path 80 b through the through hole of the sealing member 80 s, and further to the inside of the discharge tube 22 via the drop hole 80 h.

The second valve structure 90 is constructed as a check valve for supplying inert gas which allows inert gas to be supplied from a communication tube 31 into a closed space 12 b of the inner container 12 but does not allow gas to enter in a reverse direction. More specifically, the second valve structure 90 includes: a gas supply path 90 a communicating with the gas supply port 8 e described above; a valve ball moving path 90 b whose inside diameter is larger than an inside diameter of the gas supply path 90 a; and a communicating path 90 c whose inside diameter is smaller than the inside diameter of the valve ball moving path 90 b. The valve ball moving path 90 b is formed such that a shape of its vertical cross-section is circular, and therein a valve ball 91 is housed in such a manner to be able to move freely in a longitudinal direction of the moving path. On a step portion between the valve ball moving path 90 b and the communicating path 90 c, there is disposed a sealing member 90 s having a through hole (depiction omitted), and it is constructed such that the through hole is able to be closed on receiving pressing contact of the valve ball 91. The valve ball 91 is arranged not to adhere on the sealing member 90 s by pressure of inert gas supplied from the communication tube 31 via the communicating path 90 c, and to be pressed on the sealing member 90 s, when inert gas to which pressure is applied by an air pump 4 described later is blown in from the gas supply path 90 a into the valve ball moving path 90 b, by that applied pressure (larger than the supplied pressure). When the valve ball 91 is pressed, the through hole of the sealing member 90 s is closed so that pressurized inert gas is prevented from flowing backward into the communication tube 31.

(Concrete Structure of Lid Structure)

As shown in FIG. 1 to FIG. 5, the lid structure 7 is mounted on the shoulder member 8 via a hinge 27, and hereby, the lid structure 7 is capable of opening/closing the upper opening 12 a of the inner container 12. Locking of the lid structure 7 to the shoulder member 8 is performed by a lock structure (depiction omitted) constructed between the both. The lid structure 7 includes a cover plate 7 a in a shape of a bowl turned upside down, and houses the air pump (pressurizing structure) 4 in a space enclosed by the cover plate 7 a. The cover plate 7 a is made of synthetic resin, a part thereof being integrated with the discharge tube cover 9 described above. The air pump 4 is formed by bonding bellows 5 to a pump top plate 51 and a pump bottom plate 52, respectively, positioned above and below the bellows 5. In an approximate center of the pump top plate 51, there is formed a valve mounting hole 56 for mounting a valve structure 60 described later. A periphery of the valve mounting hole 56 is bent down inside the valve mounting hole 56 via a bending portion 51 a. The part bent down is to as the bent-down portion 51 b in this specification referred. In an approximate center of the pump bottom plate 52, there is penetratingly formed an opening 58 for communicating the inside and outside of the air pump 4. The air pump 4 may be integrally molded of synthetic resin.

(Structure of Pump Push Plate)

Above the air pump 4, there is disposed a pump push plate 6 to be pushed when the air pump 4 is activated. The pump push plate 6 is formed into a short cylindrical shape consisting of a circular top plate 6 j and a side wall 6 k extending downward from a periphery of the top plate 6 j, and is constructed to be able to house a part of a pump top plate 51 of the air pump 4 therein. A gas escape hole 6 d is penetratingly formed in the top plate 6 j, and on a reverse side, that is, on the pump top plate 51 side of the top plate 6 j, there is provided a valve structure main body 6 a being a part of the valve structure 60 for communicating the closed space 12 b of the inner container 12 a and the outside. The valve structure 60 in the present embodiment is constituted with the opening 58 of the pump bottom plate, the valve structure main body 6 a, and the gas escape hole 6 d. The valve structure main body 6 a will be described later. As shown in FIG. 3 and FIG. 4, on an outer peripheral surface of the side wall 6 k, there are provided protruding ridges 6 g, 6 g of a predetermined width facing each other. As shown in FIG. 3, an upper end surface of each protruding ridge 6 g is slightly lower than an upper surface of the top plate 6 j, that is, it is set such that a step portion is formed between the outer peripheral surface of the side wall 6 k and the upper surface of each protruding ridge 6 g. Incidentally, a symbol 6 f shown in FIG. 4 denotes an operation knob for operating the pump push plate 6 rotationally. The operation knob 6 f is made by forming two recessed portions adequate to accommodate fingertips on the top plate 6 j so that a part between the recessed portions can be pinched.

As shown in FIG. 3 and FIG. 4, in an approximately central portion of the cover plate 7 a comprising the outer appearance of the lid structure 7, there is formed a circular opening 7 h for housing the pump push plate 6, and on a periphery of this circular opening 7 h elongate grooves 7 g, 7 g facing each other are cut out and formed. The elongate grooves 7 g, 7 g are formed into similar figures which are slightly larger than the protruding ridges 6 g, 6 g so that the protruding ridges 6 g, 6 g can pass through them. On the other hand, as shown in FIG. 3 and FIG. 4, on a periphery of the circular opening 7 h of the cover plate 7 a, there are formed a ring-shaped opening rim 70 a protruding from an upper portion thereof in a direction of the housed pump push plate 6, and a cylindrical guide wall 70 extending downward from the upper portion as well. As FIG. 3 shows, a protrusion dimension of the opening rim 70 a is set to be slightly larger than a thickness dimension of the protruding ridge 6 g, and it is constructed such that thereby the protruding ridge 6 g is housed between the guide wall 70 and the side wall 6 k of the pump push plate 6 and at that time the upper end surface of the protruding ridge 6 g and a lower end surface of the opening rim 70 a are engaged to be able to prevent the pump push plate 6 from rising. Further, as FIG. 3 and FIG. 4 show, it is constructed such that the pump push plate 6 is able to be rotated in a horizontal direction (in a vertical direction to a paper in FIG. 3) in relation to the cover plate 7 a (guide wall 70). Therefore, housing of the pump push plate 6 into the circular opening 7 h can be performed by fitting the protruding ridges 6 g, 6 g of the pump push plate 6 into the elongate grooves 7 g, 7 g of the cover plate 7 a, making the protruding ridges 6 g, 6 g pass through the elongate grooves 7 g, 7 g, and then rotating the pump push plate 6 in a predetermined angle. After the rotation, as described above, the protruding ridges 6 g, 6 g are pressed from above by the opening rim 70 a so that the pump push plate 6 is prevented from rising. Incidentally, a symbol 6 e denotes a viewing window for allowing a display portion of a pump inner pressure gauge 57 to be seen from the outside of the pump push plate 6. The pump inner pressure gauge 57 is an inner pressure gauge for monitoring inner pressure of the air pump 4.

(Structure of Operation Lock Lid)

As shown in FIG. 1 to FIG. 4, an operation lock lid 53 is disposed between the cover plate 7 a and the pump top plate 51. The operation lock lid 53 is formed into an approximate donut shape when seen from above, and is constructed to be able to be rotated around the pump push plate 6 in a state of being sandwiched between the cover plate 7 a and the pump top plate 51. Rotation of the operation lock lid 53 is performed by operating a lock knob 54 protruding from an upper surface of the operation lock lid 53 in a rotation direction. The lock knob 54 protrudes to the outside of the cover plate 7 a via a long groove 7 d penetrating the cover plate 7 a. The operation lock lid 53 includes, as FIG. 3 shows, a tube wall portion 55 whose cross-sectional shape is a reversed L-shape, and a horizontally protruding rim 55 a which protrudes from a lower end of the tube wall portion 55 in a direction of the pump push plate 6 along the pump top plate 51. The horizontally protruding rim 55 a has a predetermined width in the rotation direction (in a direction of paper thickness in FIG. 3) of the operation lock lid 53, and the horizontally protruding rim 55 a on the observer's left side in FIG. 3 is positioned at the front of the protruding ridge 6 g in the direction of paper thickness, while the horizontally protruding rim 55 a on the right side as well is positioned at the back of the protruding ridge 6 g in the direction of paper thickness. Therefore, neither of the protruding ridges 6 g, 6 g in a state of FIG. 3 are in positions to contact the horizontally protruding rims 55 a, 55 a. Thus, it is possible to push down the pump push plate 6 without being interfered by the horizontally protruding rims 55 a, 55 a. It is set that a position at which the pump push plate 6 can be pushed down in the present embodiment is realized when the pump push plate 6 is placed at a position which makes a positioning symbol Pa and the escape hole 6 d coincide in FIG. 4, and how things are when a positioning symbol Pb and the escape hole 6 d are made coincide by rotating the pump push plate 6 clockwise is set as described in the following paragraphs.

(Vertical Motion of Pump Push Plate)

As shown in FIG. 4, when the positioning symbol Pb and the escape hole 6 d are made coincide by rotation, in association with the rotation the protruding ridges 6 g, 6 g positionally coincide with the elongate grooves 7 g, 7 g, to be released from restriction of the opening rim 70 a. At this time, the pump push plate 6 rises by a push-up structure formed between the pump push plate 6 and the guide wall 70. In the present embodiment, a spiral structure formed between the protruding ridges 6 g, 6 g of the pump push plate 6 and the guide wall 70 functions as this push-up structure. To be more precise, it is constructed such that spiral protruding ridges 70 d, 70 d protruding from the guide wall 70 and spiral grooves 6 p, 6 p formed on the protruding ridges 6 g, 6 g in correspondence with the spiral protruding ridges 70 d, 70 d are able to be screwed and coupled (the spiral protruding ridges and the spiral grooves can be in a positional relationship reverse to the above). The spiral protruding ridge 70 d and the spiral groove 6 p on the observer's left side in FIG. 3 extend upward in a direction from the front to the back of the paper, while the spiral protruding ridge 70 d and the spiral groove 6 p on the observer's right side extend upward in a direction from the back to the front of the paper as well. Therefore, by rotating the pump push plate 6 shown in FIG. 3 clockwise (in the direction from the front to the back of the paper), the pump push plate 6 can be raised. Along with this rise, the protruding ridges 6 g, 6 g pass through the elongate grooves 7 g, 7 g (see FIG. 4) to be released from the restriction of the opening rim 70 a. Incidentally, it is a matter of course that the elongate grooves 7 g, 7 g are formed to have dimensions which allow the protruding ridges 6 g, 6 g moving upward in a diagonal direction according to the spiral structure to pass through. Along with the rise of the pump push plate 6, the valve structure main body 6 a being a main component of the valve structure 60 is activated.

(Construction of Valve Structure)

A construction of the valve structure will be described based on FIG. 3. The valve structure main body 6 a is formed to have a shape able to be mounted in the valve mounting hole 56 in the pump top plate 51. More specifically, the valve structure main body 6 a is substantially constituted with a cylinder portion 6 b extending downward from a center of a lower surface of the top plate 6 j of the pump push plate 6, and a slide cylindrical body 65 able to be slidably fitted to the outside of the cylinder portion 6 b. The cylinder portion 6 b is formed to have a length to reach a position penetrating the valve mounting hole 56 of the pump top plate 51 from a back surface of the top plate 6 j, and formed to have an outside diameter as shown in FIG. 3 in relation to an inner diameter of the valve mounting hole 56. The cylinder portion 6 b includes vertical slits 6 u, 6 u reaching a position lower than the upper surface of the top plate 6 j at a time of liquid discharge (the position in which the positioning symbol Pa and the escape hole 6 d are made coincide), and includes step portions 6 w, 6 w at lower ends of the vertical slits 6 u, 6 u. A return spring 6 c is disposed in the cylinder portion 6 b.

The slide cylindrical body 65 has an inner peripheral surface slidable on an outer peripheral surface of the cylinder portion 6 b, and an outer peripheral surface slidable on a lower end of the bent-down portion 51 b of the pump top plate 51, and further has a collar flange 61 at an upper end thereof, a collar-shaped engaging protruding portion 62 at a lower end thereof, and slits 62 s, 62 s in a vertical direction, respectively. The collar flange 61 includes protruding pieces 61 a, 61 a able to fit in the vertical slits 6 u, 6 u, and on a lower surface of the collar flange 61 a ring-shaped gasket 64 is fixed. The gasket 64 is positioned between the collar flange 61 and the bending portion 51 a of the pump top plate 51, and it is constructed such that by the slide cylindrical body 65 being biased downward (in a closing direction) in FIG. 3 by the return spring 6 c, between the both, that is, the inside and outside of the air pump 4 is closed airtightly. The engaging protruding portion 62 is constructed to be able to abut on an lower end of the bent-down portion 51 b, and thereby the slide cylindrical body 65 is prevented from coming out upward.

(Opening/Closing of Valve Structure)

Opening/closing of the valve structure will be described based on FIG. 3. The valve structure 60 shown by solid lines in FIG. 3 closes the inside and outside of the air pump 4 airtightly as described above. Here, when the pump push plate 6 is rotated clockwise (from the front to back direction of the paper), the pump push plate 6 is pushed up by screw action of the spiral ridges 70 d, 70 d and the spiral grooves 6 p, 6 p. By this pushing up the cylinder portion 6 b rises, and by this rise the step portions 6 w, 6 w of the cylinder portion 6 b abut on the protruding pieces 61 a, 61 a of the collar flange 61, pulling up the slide cylindrical body 65 by further rise so that the gasket 64 is detached from the bending portion 51 a of the pump top plate 51. By this detaching, a passage is formed between the gasket 64 and the bending portion 51 a, and this passage and the slit 62 s are communicated, so that the inside and outside of the air pump 4 are communicated as a whole (see FIG. 5). More specifically, since the inside of the air pump 4 communicates with the closed space 12 b of the inner container 12 via the opening 58 of the pump bottom plate 52 while the outside of the air pump 4 communicates with the outside via the escape hole 6 d of the pump push plate 6, respectively, the opening of the valve structure 60 means communicating the closed space 12 b and the outside, that is, forming a purge passage. On the other hand, the closing of the valve structure 60 can be performed by rotating the pump push plate 6 counterclockwise (from the rear to front direction of the paper of FIG. 3) and making the screw action between the spiral protruding ridges 70 d, 70 d and the spiral grooves 6 p, 6 p work in a direction reverse to that in the case of opening, to lower the slide cylindrical body 65 together with the pump push plate 6.

As for a mechanism for vertically moving the pump push plate 6, mechanisms other than the mechanism described above can be adopted accordingly. For example, there are methods such as: a cam mechanism (depiction omitted) for vertical motion is constructed between the operation lock lid 53 and the pump push plate 6; or it is constructed such that the bellows 5 of the air pump 4 can be slightly deflected via the operation lock lid 53 and the pump top plate 51 by pushing down the lock knob 54 itself, the deflection allowing the purge passage to be opened.

(Structure of Reverse T-Letter Type Valve Operating Body)

A structure of a reverse T-letter type valve operating body will be described based on FIG. 1 and FIG. 2. The reverse T-letter type valve operating body 82 is a member for determining opening/closing of the first valve structure 80. The valve ball 81 takes charge of the opening/closing of the first valve structure 80, and it is already explained that this valve ball 81 interlocks with the crossbar 82 a. The valve operating body 82 includes this crossbar 82 a as one of components. More specifically, the valve operating body 82 is substantially constituted with this crossbar 82 a and a vertical pole 82 b standing approximately perpendicularly from the crossbar 82 a, and the vertical pole 82 b is supported by a stand supporting path 80 p which stands communicating with the slide supporting path 80 c of the shoulder member 8, an upper portion thereof extending to the side of the air pump 4 through the through hole 52 a penetrating the pump bottom plate 52. The stand supporting path 80 p is constructed to be able to allow the vertical pole 82 b to move in a lateral direction (in the right/left direction in FIG. 1) in accordance with sliding of the crossbar 82 a. The through hole 52 a also allows this moving in the lateral direction. Between an upper portion of the vertical pole 82 b positioned at the side of the air pump 4 and the lock lid 53, there is constructed a cam structure 59. The cam structure 59 is for forcibly marinating the valve operating body 82 in a state shown in FIG. 1, that is, a state that the valve ball 81 is pressed on the sealing member 81 s (a state that discharge is impossible) by engagement of a tapered surface (positioned on the back side of the paper in FIG. 1) formed on the vertical pole 82 b side and a tapered surface (hidden by the vertical pole 82 b in FIG. 1 and not seen) formed on the lock lid 53 side. As described above, the lock lid 53 is constructed to be able to be rotated in the horizontal direction by operation of the lock knob 54 (see FIG. 4), and when this lock knob 54 is in a lock state, it is the above-described state that discharge is impossible. Meanwhile, when the lock knob 54 is rotated clockwise to make the lock in a released state, in the state shown in FIG. 1 the tapered surface of the lock lid 53 moves in a direction to depart from the tapered surface of the vertical pole 82 b from the back side of the paper so that the engagement of the cam structure 59 is released. When the lock is released, moving of the vertical pole 82 b, that is, moving of the valve ball 81 via the crossbar 82 a becomes possible. In other words, discharge becomes possible.

Incidentally, it is constructed such that when the lock knob 54 is in the lock state, the horizontally protruding ridges 55 a, 55 a of the lock lid 53 in the state shown in FIG. 3 thrust below the protruding ridges 6 g, 6 g to block the pushing down of the pump push plate 6. More specifically, it is arranged such that by construction enabling the lock of the first valve structure 80 and the lock of the pump push plate 6 to be performed at the same time, liquid does not run out easily even when the liquid container 1 falls down, as well as the pump push plate 6 can not be pushed down even when it is improperly tried to be pushed down.

(Supply Structure of Inert Gas)

As shown in FIG. 1, the inner container 12 is supported from underneath by an inner container receiving tube wall 14 standing from a central portion of an inner container receiving plate 13. A space portion S is formed between the inner container receiving plate 13 and a bottom member 3 of the liquid container 1, and in this space portion S, there is disposed a gas container 15 in which nitrogen gas being inert gas is filled. Above the gas container 15, there is disposed a regulator 16 mounted on a lower surface of the inner container receiving plate 13. The gas container 15 and the regulator 16 are connected via a supply connection portion 17, and an unregulated pressure open/close valve (depiction omitted) is built in the supply connection portion 17. To the supply connection portion 17, there are connected an unregulated pressure valve knob 18 via a valve pole 19 and an unregulated pressure gauge 32 via a narrow tube 33, respectively. To the regulator 16, there is further connected a communication tube 31 having a tube shape, and an upper end of the communication tube 31 is connected to the second valve structure 90, that is, it is constructed such that inert gas is able to be supplied from the gas container 15 to the second valve structure 90. The respective members described above are combined and constitute a gas supply means in the present embodiment.

Incidentally, “nitrogen gas” used in the present embodiment means gas consisting primarily of nitrogen as inert gas. This nitrogen gas is inert to coffee and the like, and when the nitrogen gas is stored in the liquid container and substituted for air, contact between coffee and the like and air (atmosphere) is shut off, so that it can be expected that fresh flavor, taste and the like are effectively restrained from deteriorating over the future. It is considered that as inert gas, carbon dioxide gas, gas mixed of nitrogen gas and carbon dioxide gas, and other gas can be used other than nitrogen gas. For example, in a case of carbonated beverage, if carbon dioxide gas is used as inert gas, it will be possible not only to prevent oxidation and deterioration of carbonated beverage but also to prevent loss of carbon dioxide component. Further, target liquid includes, in addition to coffee, liquid drink such as, for example, alcoholic beverage, beverage containing carbonic acid, nutritional supplement, dairy product, fruit juice with pulp.

(Structure of Inert Gas Supply Source)

A structure of inert gas supply source will be described based on FIG. 6 and FIG. 7. It is preferable that the above-described gas container 15 in the present embodiment is constructed to be able to be replaced as a cartridge type container. As for a concrete structure, there can be preferably used a structure, for example, constituted with a lock ring 11 fitted into the bottom portion of the outer container 2 in a rotatable manner, and the bottom member 3 on which the gas container 15 is set. On an outer peripheral wall of the bottom member 3, a lock finger 3 a and a key 3 b are provided protrudingly, and this key 3 b is formed to be able to be fitted (inserted) into a key groove 2 b formed on the bottom portion of the outer container 2. Also, on an inner peripheral wall of the before-mentioned lock ring 11, a lock finger 11 a to be engaged with the lock finger 3 a of the bottom member 3 is provided protrudingly.

The gas container 15 is constructed to be able to be mounted to a bottom portion of the outer container by inserting the key 3 b of the bottom member 3 on which the gas container 15 is set into the key groove 2 b of the bottom portion so as not to be rotated, and further by locking the peripheral wall of the bottom member 3 by rotation of the lock ring 11. The lock by the lock ring 11 is performed by engagement of the lock finger 11 a which the lock ring 11 has and the lock finger 3 a which the bottom member 3 has. Incidentally, instead of using the replaceable gas container 15, a gas container may be constructed on the bottom member 3 in a fixable manner and it may be structured such that inert gas is able to be replenished from the outside via a gas supply valve (depiction omitted) such as a nipple disposed on the fixed gas container accordingly.

(Usage of Liquid Container)

Usage of the liquid container will be described with reference to FIG. 1 to FIG. 5. Here, stored liquid is coffee. First, lock of the lid structure 7 (depiction omitted) is released to open the lid structure 7 in relation to the outer container 2 (see FIG. 2). By opening, the closed space 12 b is also opened, and the upper opening 12 a of the inner container 12 is exposed. Here, coffee brewed in advance is poured into the inner container 12. When pouring is finished, the lid structure 7 is closed and locked. At this time, in the closed space 12 b of the inner container 12, coffee and the atmosphere exist in a mixed manner. Subsequently, substitution operation of the atmosphere and inert gas is performed. First, when the pump push plate 6 is rotated clockwise to make the positioning symbol Pb and the escape hole 6 d coincide (see FIG. 4), the pump push plate 6 rises by action of a push-up structure along with the rotation. By the rise of the pump push plate 6, the valve structure 60 opens so that the closed space 12 b and the outside becomes in a communicating state via the inside of the air pump 4. Here, by operating the supply connection portion 17, inert gas is supplied from the gas container 15 to the second valve structure 90 via the communication tube 31. Supplying of inert gas may be started before the rotating operation of the pump push plate 6.

Inert gas supplied to the second valve structure 90 flows into the closed space 12 b while moving the valve ball 91 in the opening direction by a predetermined pressure. By flowing in of inert gas, pressure in the closed space 12 b heightens so that gas (the atmosphere and inert gas) existing in the closed space 12 b flows to the outside, that is, through the opening 58 of the pump bottom plate 52 into the air pump 4, further to out of the air pump 4 via the valve structure 60, and further to the outside via the escape hole 6 d of the top plate 6 j. In the beginning of the flowing in of inert gas, concentration of inert gas is lower than concentration of the atmosphere, but as the flowing in of inert gas and the flowing out of the inside gas are continued, this ratio is gradually diluted so that finally the ratio is reversed or gas is substituted. When a certain time passes, substitution of the atmosphere with approximate inert gas in the closed space 12 b is completed. When inert gas atmosphere is realized, the pump push plate 6 is now rotated counterclockwise to make the positioning symbol Pa and the escape hole 6 d coincide (see FIG. 4), so that the pump push plate 6 moves downward along with rotation and the valve structure 60 is also closed.

By closing of the valve structure 60, the inside of the air pump 4 and the inside of the closed space 12 b become in an inert gas atmosphere and in a state that contact of coffee and the atmosphere is shut off. Even in this state, inert gas is still in a state able to be supplied and is continued to be supplied until a predetermined pressure is reached. Here, it is arranged such that if pressure inside the closed space 12 b exceeds the predetermined pressure for some reason the pressure pushes up the slide cylindrical body 65 of the valve structure 60 to be opened for letting out inert gas automatically. More specifically, the valve structure 60 has a function not only as a purge valve at a time of substituting the atmosphere with inert gas but also as a safety valve for making pressure in the closed space 12 b (inside the air pump 4) back to an adequate value when the pressure exceeds the predetermined value. Incidentally, setting of the adequate value of pressure in the closed space 12 b can be performed by selecting biasing force of the return spring 6 c which the valve structure 60 has. If the pressure of inert gas exceeds the predetermined adequate value for some reason (for example, vapor pressure generated from coffee), the valve structure 60 opens automatically to adjust the pressure.

Next, coffee is discharged. Discharge of coffee is performed by rotating the lock knob 54 shown in FIG. 4 clockwise to make the first valve structure 80 in a state able to be opened and pushing down the pump push plate 6. When the pump push plate 6 is pushed down, along therewith the bellows 5 of the air pump 4 are contracted and thereby inert gas in the air pump 4 flows into the closed space 12 b via the opening 58. The contracted bellows 5 stretch by themselves and return to the original state when the press-down force ceases. By the flowing in of inert gas, the inert gas in the closed space 12 b is pressurized the pressure rises. The pressurized inert gas presses a liquid surface of coffee to push up coffee into the draw pipe 21. The coffee pushed up moves the valve ball 81 of the first valve structure 80 against biasing force of the coil spring 80 f in the opening direction and flows therethrough to be discharged from the discharge tube 22 to the outside. The pressure in the closed space 12 b lowered by discharge of coffee is replenished by inert gas supplied continually from the gas container 15 and the pressure is maintained at the approximately predetermined value. When the pump push plate 6 is pushed down several times, coffee is discharged and inert gas is supplied every time.

First Modification Example of the Present Embodiment

A first modification example of the present embodiment will be described based on FIG. 8 and FIG. 9. Difference between the present embodiment described above and a first modification example is that the latter does not have an air pump which the former has and that the discharge valve of the former opens/closes automatically while a discharge valve of the latter is dependent on user's operation. Therefore, in the following description, a focus will be placed on parts related to these two points, and as for parts common to the both, the same reference numerals and symbols used in FIG. 1 to FIG. 7 will be used in FIG. 8 and FIG. 9 and description will be omitted in the extent possible. A second modification example described later will be treated in the same way except that drawings applied are different.

A liquid container 1A shown in FIG. 8 and FIG. 9 has a shoulder member 8. The shoulder member 8 have an opening in the center thereof which communicates with a closed space 12 b and this opening is closed airtightly by an inner lid 40. The inner lid 40 includes a top plate 41 which is thinner than a periphery, and a cylindrical inner wall 42 extending downward from a lower surface of the top plate 41. The inner wall 42 is constructed such that a male screw portion formed on an outer periphery thereof is able to be screwed in a female screw portion of the shoulder member 8, and it is constructed such that the inner lid 40 is able to be attached airtightly to the shoulder member 8 by this screwing and a packing 40 p disposed between the both. On the top plate 41, there are provided a valve structure 60′ and an inner lid plug (inner lid joint, pouring check valve) 43.

(Construction of Valve Structure)

The valve structure 60′ combines a purging function and a function as a safety valve, similarly to the valve structure 60 according to the present embodiment. The valve structure 60′ is inserted into a mounting hole 41 h penetrating the top plate 41, having a shape similar to a bobbin as a whole. The valve structure 60′ has an upper flange portion 60′c and a lower flange portion 60′b respectively above and below a cylindrical body 60′a, and inside the cylindrical body 60′a a spring 60′s is disposed. The spring 60′s supports a projection 63 from underneath via a movable plate 60′d positioned at the top thereof such that the projection 63 is able to rise and set freely. The upper flange portion 60′c has a function of making the top plate 41 support the entire valve structure 60′ by being engaged with a periphery of the mounting hole 41 h from above via a ring-shaped packing 60′p. A symbol 63 a denotes a bridge member for assisting self-support of the projection 63. The bridge member 63 a allows rising and setting of the projection 63. As shown in FIG. 8, the lid structure 7 includes a cylindrical peripheral wall 70 b extending downward from a bottom surface of a cover plate 7 a, and the peripheral wall 7 b is constructed to abut on a tip of the projection 63 and to be able to press this at a time of closing of a lid structure 7. As shown in FIG. 9, pressing by the peripheral wall 7 b is arranged to be released by opening of the lid structure 7.

Since the valve structure 60′ at a time of receiving pressing of the peripheral wall 7 b is pressed on the top plate 41, airtightness is maintained between the ring-shaped packing 60′p and the periphery 41 e of the mounting hole 41 h, but, when the pressure of the closed space 12 b becomes a predetermined value and above for some reason, the pressure tries to push up the valve structure 60′ by acting to the lower flange portion 60′b. When this force of pushing up exceeds biasing force of the spring 60′s, the force pushes up the valve structure 60′ against the biasing force of the spring 60′s. It is constructed such that by this pushing up, airtightness between the ring-shaped packing 60′p and the periphery 41 e of the mounting hole 41 h is released so that the inside gas is able to escape. Therefore, it means that selection of the biasing force of the spring 60′s determines a value of an appropriate pressure. On the other hand, as shown in FIG. 9, even if the lid structure 7 is opened to release the pressing against the projection 63, the valve structure 60′ does not immediately release airtightness between the ring-shaped packing 60′p and the periphery of the mounting hole 41 h because of its own weight, but opening becomes easier as the pressing force is absent. More specifically, the valve structure 60′ is constructed to function as the safety valve when the lid structure 7 is closed and as the gas vent valve (purge valve) for substituting the atmosphere with inert gas when the lid structure 7 is opened, respectively. A method of substitution of inert gas is as explained in the description of the present embodiment, but when the liquid container 1A is used, it is preferable to make the inside of the closed space 12 b of the inner container 12 in an inert gas atmosphere before coffee is supplied. Though a procedure is possible in which coffee is supplied while the atmosphere in the inner container 12 is withdrawn via the valve structure 60′ and then inert gas is supplied, there are fewer occasions in which supplied coffee contacts the atmosphere when the inert gas atmosphere is realized in advance, and it is preferable for deterioration prevention. Incidentally, it is constructed such that the pressure in the closed space 12 b is able to be monitored by an inner pressure gauge 57′.

(Construction of Inner Lid Plug)

The inner lid plug (pouring check valve) 43 formed on the top plate 41 is set to have a height which does not influence closing of the lid structure 7, and it is arranged such that the inner lid plug 43 is used with the lid structure 7 being open as shown in FIG. 9. The inner lid plug 43 is a plug for enabling coffee (liquid) to be supplied into the inner container 12 without removing the inner lid 40, that is, without opening the closed space 12 b. The inner lid plug 43 is constituted with: a cylindrical body 43 a standing from an upper surface of the top plate 41; a hollow portion 43 b penetrating the cylindrical body 43 a in a vertical direction; a bottom portion 43 c with a hole closing a lower portion of the hollow portion 43 b; a packing 43 d with a hole closing an upper portion of the hollow portion 43 b; a spring 43 e mounted on the bottom portion 43 c in the hollow portion 43 b; and a check valve 45 biased from underneath by the spring 43 e. It is preferable that the cylindrical body 43 a is constructed integrally with the top plate 41 for easier manufacturing, but it can be constructed separately. A tip of the check valve 45 is constantly pressed on the packing 43 d with a hole in a repulsive manner by the spring 43 e and it is arranged that thereby the hollow portion 43 b is closed airtightly in an openable manner. On an upper periphery of the cylindrical body 43 a, a ring-shaped receiving groove 43 f is formed. The bottom portion 43 c is formed such that a part thereof protrudes from a lower surface of the top plate 41, and to the protruding part, a liquid supply tube 44 is connected.

An lower end of the liquid supply tube 44 extends downward to a predetermined stored liquid surface. The reason for extension downward to the stored surface is that in a case that coffee is poured from the inner lid plug 43, coffee poured blocks an opening of the liquid supply tube 44 and prevents further pouring when the stored surface of coffee stored in the inner container 12 reaches an lower end of the liquid supply tube 44, and thereby pouring of coffee stops automatically. More specifically, the liquid supply tube 44 is equipped with a function of enabling a predetermined amount of coffee to be supplied automatically. Therefore, a liquid surface of the inner container 12 according to which supply of liquid automatically stops, that is, a required amount of liquid stored in the inner container 12, can be determined by selecting a length of the liquid supply tube 44 accordingly.

A symbol 95 denotes a liquid pouring joint with a check valve which is mounted on a tip of a liquid supply pipe 96. The liquid pouring joint 95 is a column-shaped member having an outside diameter slightly larger than an outer diameter of the cylindrical body 43 a of the inner lid plug 43, and is constructed to be able to be coupled with the inner lid plug 43. The liquid pouring joint 95 is constituted with: a joint main body 95 a; a receiving recessed portion 95 b formed to be able to receive a tip of the cylindrical body 43 a (see an enlarged view in FIG. 9) on a coupling end of the joint main body 95 a (lower end in FIG. 9); a ring-shaped protruding piece 95 c able to be inserted into the receiving groove 43 f which is placed near a mouth of the receiving recessed portion 95 b; a hollow path 95 e penetrating the joint main body 95 a and communicating with the receiving recessed portion 95 b; a receiving packing 95 f with a hole which is disposed on the hollow path 95 e side in the receiving recessed portion 95 b; a closing packing 95 d with a hole which is disposed on the receiving recessed portion 95 b side in the hollow path 95 e; a lid body 95 g with a hole which closes a mouth of the hollow path 95 e; a spring 95 h disposed in the hollow path 95 e; a check valve 95 j biased in a direction of the closing packing 95 d by the spring 95 h; and a projection 95 k projecting from the check valve 95 j. The check valve 95 j is constantly pressed on the closing packing 95 d by biasing force of the spring 95 h, and it is arranged such that, hereby, communication between the receiving recessed portion 95 b and the hollow path 95 e is shut off airtightly. As for the projection 95 k of the check valve 95 j, a tip thereof is positioned in the receiving recessed portion 95 b by penetrating the hole of the closing packing 95 d and the hole of the receiving packing 95 f As for the lid body 95 g with a hole, a part thereof projects from the joint main body 95 a, and to this projecting part the liquid supply pipe 96 is connected.

Here, when the liquid pouring joint 95 is coupled with the inner lid plug 43, an upper portion of the inner lid plug 43 is received by the receiving recessed portion 95 b, and at this time, an upper end of the former abuts on the receiving packing 95 f as well as the ring-shaped protruding piece 95 c is fitted into the receiving groove 43 g in a detachable manner.

At a time of fitting in, the projection 95 k abuts on the check valve 45 as shown in the enlarged view in FIG. 9. By this abutting, the check valve 45 is pushed in to open the hole of the packing 43 d with a hole, while the check valve 95 j is also pushed back slightly by biasing force of the spring 43 e to open the hole of the closing packing 95 d. At this time, the liquid supply pipe 96 communicates with the closed space 12 b via the liquid pouring joint 95 and the inner lid plug 43. More specifically, it becomes in a state that coffee is able to be poured (able to be supplied). It is preferable that pouring of coffee is performed using pressure of inert gas supplied by a not-shown inert gas supply device. It is because in pouring by inert gas coffee is pushed by inert gas and moves in the liquid supply pipe 96 and inert gas does not harm the inert gas atmosphere in the closed space 12 b even if it is supplied with coffee or after coffee.

According to the liquid container 1A, since coffee can be poured via the inner lid plug 43, it is not necessary to open the lid structure 7 except for cleaning and the like of the inside of the inner container 12 and the like, as long as the inner lid plug 43 is used. This makes it possible, first, that the inside of the vacant inner container 12 is made into the inert gas atmosphere in advance and then coffee is poured. Then, it makes it possible, secondly, that coffee is poured into the inner container 12 which has become empty again or has small amount of stored coffee due to discharge, with the inert gas atmosphere being maintained. In the former case, occasions in which coffee contacts the atmosphere can be reduced compared to a case that coffee is supplied with the lid structure 7 being open, and in the latter case, if coffee is replenished repeatedly until a time of cleaning and the like, inert gas substitution is not necessary to be performed successively. The same can be applied to a liquid container 1B described later.

(Construction of Discharge Valve)

A discharge valve 100 includes: a sealing member 101 with a hole; a valve ball 102 capable of pressing the sealing member 101 with a hole; a valve ball moving path 103 for moving the valve ball 102 in opening/closing directions; a bar-shaped valve operating body 104 fixed to the valve ball moving path 103; supporting portion 105 supporting the valve operating body 104 in such a manner to be able to move airtightly; and a spring 106 for constantly biasing the valve ball 102 in the closing direction which is disposed in the valve ball moving path 103. The valve operating body 104 is constructed to be able to move with the valve ball 102 in the opening/closing direction by rotational operation of an operating lever 108 via a cam structure 107. More specifically, the valve ball 102 is constantly pressed on the sealing member 101 with a hole by biasing force of the spring 106 and the discharge valve 100 is in a closing state, and when the operating lever 108 is rotationally operated, the valve operating body 104 is pulled in the opening direction (from the right to left direction in FIG. 8) by action of the cam structure 107, and along therewith the valve ball 102 is also pulled in the same direction so that airtightness with the sealing member 101 with a hole is released. More specifically, the discharge valve 100 becomes in the opening state. Incidentally, it is a matter of course that the biasing force of the spring 106 is set to be larger than the pressure of inert gas supplied in the closed space 12 b. It is because if the biasing force is smaller, it is not possible to maintain the discharge valve 100 in the closing state.

To the inert gas supplied from the communication path 31 to the closed space 12 b, there is provided a pressure (for example, 0.001 to 0.1 MPa) sufficient to press the liquid surface to push up coffee into the draw pipe 21. Therefore, when coffee is to be discharged from the inner container 12, coffee can be discharged by merely operating the operating lever 108 to open the discharge valve 100. More specifically, by opening of the discharge valve 100, coffee pushed up by inert gas flows through the discharge valve 100 and is discharged to the outside from a discharge tube 22. Therefore, it is not necessary to operate a pump push plate as in the case of using the liquid container 1 according to the present embodiment, and as a result, operation is easier. According to the liquid container 1A, as in the liquid container 1 described above, contact of coffee stored in the inner container 12 and the atmosphere can be shut off, and therefore deterioration of coffee can be effectively restrained for the future. Further, according to the liquid container 1A, it is not necessary to mind the stored amount of coffee when pouring or replenishing coffee into the inner container 12. It is because supply is shut off automatically without being minded when a predetermined amount is poured.

Second Modification Example of the Present Embodiment

A second modification example of the present embodiment will be described based on FIG. 10 to FIG. 14. A liquid container 1B according to the second modification example of the present embodiment is constructed such that liquid can be stored and discharged basically by the same principle of operation as that of the liquid container 1A according to the above-described first modification example. The liquid container 1B largely differs from the liquid container 1A in a supply structure of inert gas and a structure of a purge valve. They are different in the point that while the latter adopts the second valve structure for preventing flow back of inert gas by pressuring, the former omits one but make a regulator take on such a role, and in the point that while in the latter the valve structure combines the purge function and the safety valve function, in the former such a valve structure is constituted with separate valves. Hereinafter, description will be performed with a focus being placed on these different points. Incidentally, as for members common to the present embodiment, description will be performed only for necessary ranges as described above.

On an upper portion of an outer container 2 of the liquid container 1B shown in FIG. 10 to FIG. 14, a lid structure 141 is mounted in an openable/closable manner. The lid structure 141 includes a lid structure main body 143 hinged to the outer container 2 and a cap portion 144 able to be opened/closed which is provided on a top portion of the lid structure main body 143. On the outer container 2, a shoulder portion 151 is provided, and in a central portion of the shoulder portion 151 there is formed an opening communicating with a closed space 12 b of an inner container 12. In the lid structure main body 143, inner lid 153 and a packing 152 are provided, and it is constructed such that when the lid structure 141 is closed the packing 152 adheres on the shoulder member 151 and the inner lid 153 so that the inner lid 153 is able to close the closed space 12 b airtightly. The lid structure 141 is constructed such that the lid structure main body 143 and the outer container 2 are firmly locked by a lock structure (depiction omitted) constructed between the both. The cap portion 144 is penetrated by long holes 144 h, . . . for letting out air. A symbol 146 denotes a cover member mounted on a back surface of the outer container 2 via a hinge 148 able to be attached/detached. The cover member 146 is a member for covering a supply structure of inert gas described later, and is constructed to be able to expose the supply structure of inert gas when opened as shown by an imaginary line in FIG. 13, for example.

On the inner lid 153, there are provided four valves communicating the inside and outside of the inner lid 153, namely, a supply valve 161, an exhaust valve 162, a purge valve 163 and a liquid supply valve 164. The former two are valves operated manually and the latter two are valves operating automatically. The supply valve 161 is a valve for supplying inert gas supplied via a supply pipe 167 into the closed space 12 b. The exhaust valve 162 is a valve for exhausting the atmosphere in the closed space 12 b by being opened as inert gas is supplied. The exhaust valve 162 constitutes a valve structure for letting out the atmosphere according to the second modification example. The purge valve 163 has a function of maintaining the pressure in the closed space 12 b within a predetermined value by opening automatically when the pressure in the closed space 12 b becomes a predetermined value and above. The purge valve 163 can be omitted by giving adequate consideration on a structure of a supply source of inert gas, intensity of a member or structure enclosing the closed space 12 b, installation of a purge means other than the purge valve 163, or the like. The supply valve 161 has the same structure and function as the inner lid plug 43 (see FIG. 8) according to the first modification example.

On the closed space 12 b side of the liquid supply valve 164, a liquid supply tube 166 is mounted. The liquid supply tube 166 has the same function as that of the above-described liquid supply tube 44 (see FIG. 8). A part or the whole of the supply pipe 167 is constructed to be flexible (have flexibility) and the supply pipe 167 has play of sufficient length so as to be able to follow opening/closing of the lid structure 141. Therefore, the supply pipe 167 is able to loosen when the lid structure 141 is in a closing state and to stretch when the lid structure 141 is in an opening state. A symbol 168 denotes a discharge valve provided on a discharge tube 22, the discharge tube 22 being directly connected to a draw pipe 21. More specifically, it is arranged such that when the discharge valve 168 is opened in a state that inert gas is supplied, coffee which receives pressure of inert gas is pushed up into the draw pipe 21 and flows through the discharge tube 22 to be discharged to the outside.

It is possible to pour coffee directly into the inner container 12 by opening the lid structure 141, but, if pouring is performed via the liquid supply valve 164, an advantage is common to the liquid container 1A in that the lid structure 141 is not required to be opened/closed. Further, in a case of pouring in association with opening/closing of the lid structure 141, due to opening thereof the atmosphere enters inside the closed space 12 b of the inner container 12, and withdrawing operation of the atmosphere such as reopening the exhaust valve 162 is required, but by pouring coffee via the liquid supply valve 164 while preventing the atmosphere from entering, it is possible to store and discharge coffee without performing withdrawing operation of the atmosphere. This saves the effort of withdrawing the atmosphere and is quite convenient not only when coffee is poured into an empty inner container 12 but also when coffee is replenished into the inner container 12 in which coffee still remains.

(Inert Gas Supply Structure)

An inert gas supply structure will be described based on FIG. 10 to FIG. 13. A supply structure of inert gas (gas supply means) 171 is substantially constituted with a gas tank 172 for storing inert gas, and a regulator 176 for reducing gas pressure of the gas tank 172, and an output side of the regulator 176 is connected to the supply valve 161 via the supply pipe 167. The regulator 176 includes a handle 178 for pressure adjustment, and it is arranged such that the handle 178 is able to be operated from the outside of the cover member 146. It is constructed such that gas pressure inside the supply pipe 167 is able to be monitored by a digital pressure gauge 177. A display portion of the digital pressure gauge 177 is faced outside from a window portion 147 provided on the cover member 146, and it is constructed such that pressure can be read in a state that the cover member 146 is closed. It is constructed such that inner pressure of the gas tank 172 is able to be monitored by a pressure gauge 173, and it is constructed such that inert gas is able to be filled into the gas tank 172 from the outside (for example, inert gas generating device) via the valve 174. By making inert gas able to be filled, replacement of the gas tank 172 becomes unnecessary as well as the gas tank 172 can be used repeatedly, and therefore it is economical. A symbol 175 denotes a valve for releasing inert gas which is disposed between the gas tank 172 and the regulator 176. The regulator 176, digital pressure gauge 177 and the like are screwed on the outer container 2 via a mounting member 179.

When the pressure of the inert gas supplied into the closed space 12 b is set to be 0.001 to 0.1 MPa, more preferably, 0.003 MPa and below, results are good, according to an experiment performed by the inventors. More specifically, pressure of supplied inert gas is necessary to be higher than atmospheric pressure in order to push up stored coffee, but if the pressure is lower than 0.001 MPa, the pressure is too weak and it takes too much time to withdraw liquid, which cannot be regarded as smooth, and if the pressure exceeds 0.1 MPa, the pressure is too high and liquid may be sprinkled when liquid comes out from the discharge valve, which cannot be regarded as smooth. However, it is a matter of course that whether withdrawal is smooth varies according to dispositions (kinds of ingredients, difference in viscosity) of liquid to be withdrawn, a diameter of the draw pipe, a shape of the discharge valve, and the like.

(Over-Time Change of Stored Coffee)

Over-time change of stored coffee will be described based on FIG. 15 to FIG. 17. An experiment is performed about over-time change of stored coffee, using the liquid container 1B according to the second modification example. Experimental items and analytical instruments are as shown in a table of FIG. 15. Coffee being an experimental object is obtained by the following procedure. First, coffee is brewed twice from ground coffee using a predetermined amount of hot water, and the brewed coffee is mixed. Half of the mixed coffee is poured into the liquid container 1B, and the other half is poured into a liquid container C (description omitted) equivalent to the liquid container 1B, by opening lid structures, respectively. Then, immediately, inert gas (nitrogen gas) is supplied (pressure 0.002 MPa) into the liquid container 1B, and simultaneously with the supply, the exhaust valve 162 is opened for approximately 90 seconds to make the inside of the closed space 12 b be in an inert gas atmosphere (see FIG. 13). The inside of the liquid container C is filled with the atmosphere. Experimental results are as shown in tables of FIG. 16. Rates of change in tables of FIG. 16 denote measured value rates at every elapsed time (60 minutes, 180 minutes, 480 minutes), with a measured value at an elapsed time after brewing (vertical axes in the tables) at 0 (zero) minute being “1”. Incidentally, in the following description, the coffee stored in the liquid container 1B is referred to as “Coffee 1B” and the coffee stored in the liquid container C is referred to as “Coffee C”, respectively.

From the above-described experimental results, the following is found out. That is, there are very few changes in Brix (solid content) in both Coffee C and Coffee 1B. As for pH's (hydrogen ion activity indexes), they decrease with over-time deterioration, but decreasing speed of Coffee C is faster than that of Coffee 1B. As for acidity, it increases in both Coffee C and Coffee 1B as time elapses, but percentages of increase of the former is higher. As for turbidity (OD720, optical density 720 nm), it increases in both Coffee C and Coffee 1B as time elapses, but differences in percentages of increase between the both are most remarkably shown among respective analysis items. Coffee 1B has approximately the same liquid color as that after brewing and very few changes are found in its turbidity even after time elapses, while Coffee C becomes darker as time elapses.

Results of sensory evaluation are as shown in charts of FIG. 17. The sensory evaluation is performed by a method of drinking coffee discharged at every elapsed time and evaluating five items of scent, bitterness, acidity, body, and aftertaste in five-point scale. As for evaluation criteria, 0 (zero) minute after brewing is a benchmark, and coffee after time (Coffee C, Coffee 1B) and new coffee (Coffee D) brewed freshly per sense as after 0 (zero) minute are compared to be graded. A grade 4 is a benchmark value (taste of Coffee D at zero minute after brewing), and a point method is that the higher the number is the better the grade is while the lower the number is the worse the grade is. In the charts, it is shown that the larger the area enclosed by lines the lesser deterioration is. More specifically, after 60 minutes after brewing, there is very little difference between Coffee C and Coffee 1B. However, after 180 minutes, little deterioration is seen in Coffee 1B, while substantial deterioration is seen in Coffee C. At this time, taste and liquid color of Coffee 1B is not much different from that of Coffee D. After 480 minutes, deterioration is seen in both Coffee C and Coffee 1B, but degree of deterioration of the former is larger than that of the latter, and the former is tinged with black and the latter is tinged with red, respectively. By checking the above-described sensory evaluation and various analytical values, it is found that according to the liquid container 1B taste of Coffee 1B is able to be maintained for a long time. Therefore, when coffee brewed in early morning is stored and discharged in small portions, at an office and at home, as well as at a restaurant and at a coffee stand in a rail way car or the like, for example, it is possible to provide coffee whose taste is virtually unchanged from the time of brewing at least until evening.

INDUSTRIAL AVAILABILITY

As described above, by a liquid container according to the present invention, it is possible to effectively restrain oxidation deterioration of stored liquid and to maintain the restraining effect when the stored liquid is discharged in small portions. 

1. A liquid container comprising: an outer container; an inner container having a heat retaining property which is housed in said outer container; a lid structure capable of forming a closed space in said inner container by closing an upper opening of said inner container airtightly in an openable/closable manner; a gas supply means for supplying inert gas of a predetermined pressure into the closed space of said inner container; a valve structure enabling the closed space of said inner container and the outside to be communicated; a draw pipe for guiding liquid stored in said inner container to out of said outer container via the closed space; and a discharge valve provided to said draw pipe; wherein it is constructed such that the stored liquid is able to be discharged by pressure of supplied inert gas at a time of opening of said discharge valve.
 2. The liquid container according to claim 1, wherein said lid structure comprises a purge valve purging automatically when pressure in said closed space is at a predetermined value and above.
 3. The liquid container according to claim 1 or claim 2, wherein said lid structure comprises a pressurizing structure for pressurizing the supplied inert gas.
 4. The liquid container according to claim 3, wherein said pressurizing structure comprises bellows between a top plate and a bottom plate, and wherein it is constructed such that an air pump and the closed space are able to be communicated via an opening formed on the bottom plate.
 5. The liquid container according to claim 3 or claim 4, wherein said discharge valve is constituted with a check valve opening automatically in an automatically recoverable manner by pressurizing of inert gas by said pressurizing structure.
 6. The liquid container according to any one of claim 3 to claim 5, wherein said gas supply means includes a gas passage sending inert gas to the closed space and a gas supply source, and in said gas passage a check valve for gas is provided.
 7. The liquid container according to any one of claim 1 to claim 6, wherein said gas supply means is provided with a regulator for adjusting pressure of inert gas.
 8. The liquid container according to claim 1 or claim 2, wherein pressure of inert gas in the closed space is set to be 0.001 to 0.1 MPa.
 9. The liquid container according to any one of claim 1 to claim 8, wherein said lid structure includes a pouring check valve for pouring liquid into the closed space. 